Prominent on the nation's research agenda on drug abuse treatment is the development of effective behavioral and pharmacological treatment approaches. Likewise, there is concern about transferring this knowledge to practitioners to foster adoption within the service delivery system. The proposed dissertation addresses a facet of this mission using a theoretical framework outlined by Rogers (1995), to examine the impact of managerial characteristics, internal structural characteristics, and external characteristics on the adoption of naltrexone. Data for these analyses will be derived from the National Treatment Center Study (NTSC), a longitudinal national sample of 450 private treatment facilities spanning from 1994 to 2003. The NTCS focuses exclusively on the organization as the unit of analysis, with the administrators and/or clinical directors providing the organizational-level data during on-site interviews. The objectives of the proposed dissertation are two-fold. First, in order to address the adoption of this innovative treatment approach longitudinally, a discrete-time event history analysis will be performed. This approach will allow for the study of the occurrence and timing of events surrounding naltrexone adoption. Second, the focus will turn to treatment centers that have adopted naltrexone and, using Rogers' (1995) theoretical propositions on the diffusion of innovations, create a categorical typology of adopters based on innovativeness. This adopter continuum includes five adopter categories: innovators, early adopters, early majority, late majority, and laggards. After plotting those centers adopting naltrexone by the year of adoption and identifying into which category they should be placed, a multinomial logistic regression will be performed using the five adopter categories as the dependent variable. Organizational-level factors, internal organizational structure, externalities, and stated reasons for adoption, will be the major concepts included in predicting adopter categorization.